The present invention relates in general to clutch actuators that are used to engage and disengage a clutch that is associated with an engine. More specifically, the present invention relates to a clutch actuator linkage that is used in cooperation with a clutch that is operably connected to an engine. The clutch includes a clutch operating shaft that cooperates with the clutch actuator linkage so as to transition the clutch from a disengaged condition to an engaged condition and then return from an engaged condition to a disengaged condition.
In a broad, conceptual sense, clutches are considered to be well known mechanisms. While the engaging and disengaging configurations or mechanisms can assume a variety of forms and constructions, clutches (generally) are constructed and arranged for use in conjunction with two rotating shafts such as a motor vehicle engine and its manual transmission. Clutches are also found in other devices, such as cordless drills and chain saws, as only a couple of other examples.
A typical clutch configuration connects the two shafts so that they can either be locked together and rotate at the same speed or de-coupled and rotate at different speeds. In a motor vehicle, depressing the clutch pedal disengages the clutch from the engine. In other clutch designs, the engaging and disengaging mechanism and method may be different. For example, a clutch may be engaged and disengaged by the use of a hand lever connected to one end of an operating shaft. Turning or rotating the clutch operating shaft about its longitudinal axis turns a throw out yoke for the desired engagement with other portions of the clutch structure. A representative example of such a construction is offered by Arrow Engine Company of Tulsa, Okla. by its clutch model No. C-110-HP-3. This type of clutch actuator would be compatible for engaging a clutch on any engine utilizing a power take off (PTO) type clutch where it is necessary to use linear motion to engage or disengage a clutch mechanism. A good example of this application would be the C-Series engine also offered by Arrow Engine Company. These gas engines are constructed and arranged for continuous duty use in oil fields for powering a pump jack, as one example. Since these types of engines and clutches do not lend themselves to incorporation of a clutch pedal, the referenced hand lever has been provided. However, use of the hand lever requires a human presence and considering the size and location of the clutch and engine, an automated linkage to actuate the clutch (i.e., engage and disengage) is seen as an improvement.
One type of automated device for a clutch linkage is offered by F.W. Murphy (United Kingdom) with its U.S. facility in Tulsa, Okla., as model No. CO3. The CO3 product is described as an “electric motor driven clutch operator for engine automation systems”. This electronic controlled and driven design requires various component controls such as limit switches, or the like, in order to control the travel of linkage and/or clutch components.
The disclosed structure, as presented herein, approaches the automated actuator design in a manner that is different from the F.W. Murphy CO3. The structure disclosed herein uses a linear actuator and a unique linkage to turn the clutch operating shaft. By taking advantage of the over-center clutch design in terms of its operating shaft, the disclosed structure is able to substantially eliminate any noticeable clutch pre-load that might otherwise be applied to the clutch operating shaft according to various prior art designs. Importantly, the clutch that is associated with the disclosed clutch linkage, as described herein, has a structural configuration that incorporates an over-center position between the clutch-disengaged position and the clutch-engaged position. The force requirements to rotate or turn the clutch operating shaft increase as the clutch operating shaft approaches that over-center position. When the clutch operating shaft snaps or pops through this over-center position, the clutch is engaged and no further force is required to maintain the clutch-engaged position by means of the clutch operating shaft and the disclosed actuator linkage.